Khalid Haneen Abass, Spray Pyrolysis Deposition and Effect of Annealing Temperature on Optical Properties of Cu:NiO Film, ILCPA Volume 47, International Letters of Chemistry, Physics and Astronomy (Volume 47)
https://www.scipress.com/ILCPA.47.178
Abstract:
    Spray pyrolysis method that used to prepare Cu:NiO thin films onto glass substrate with various annealing temperature. Spectral transmittance of prepared thin films determined by UV-Visible spectrophotometer in the range of (380-900) nm. The transmittance decreased with increasing annealing temperature. While the absorption coefficient and extinction coefficient increased with increasing annealing temperature. Energy gap decreased from 2.9 eV before annealing to 2.78 eV after 500 °C annealing temperature.
Keywords:
    Cu, Energy Gap, NiO, Optical Properties, Thin Film